In many engines with fuel injection systems, it is desirable to supply liquid fuel to the injector or injectors at a pressure which is either constant relative to atmospheric pressure or varies so that it is constant relative to the pressure drop across the injectors when open which is a function of the intake manifold pressure of the combustion air. Both the combustion air pressure and the flow of fuel supplied to the engine varies with engine speed, load and other operating conditions.
Previously, a variety of fuel pressure regulators have been developed one of which is shown in U.S. Pat. No. 5,579,739. This regulator has a generally flat, flexible diaphragm disposed between two chambers and subjected to manifold pressure on one side and pressurized liquid fuel on the other side. In use, this regulator does not achieve or maintain a uniform and constant differential fuel pressure across the injectors. Rather, the differential fuel pressure varies with the rate of fuel flow and drops as fuel consumption increases. This inconsistent pressure differential across the fuel injectors adversely affects the performance of the engine. Additionally, this regulator does not compensate for dynamic pressure losses in the fuel system between the regulator and the injectors.